We analysed 68 candidate planetary systems first identified during Campaigns 5 and 6 (C5 and C6) of the NASA K2 mission. We set out to validate these systems by using a suite of follow-up observations, including adaptive optics, speckle imaging, and reconnaissance spectroscopy. The overlap between C5 with C16 and C18, and C6 with C17, yields light curves with long baselines that allow us to measure the transit ephemeris very precisely, revisit single transit candidates identified in earlier campaigns, and search for additional transiting planets with longer periods not detectable in previous works. Using vespa, we compute false positive probabilities of less than 1 per cent for 37 candidates orbiting 29 unique host stars and hence statistically validate them as planets. These planets have a typical size of 2.2 R⊕ and orbital periods between 1.99 and 52.71 d. We highlight interesting systems including a sub-Neptune with the longest period detected by K2, sub-Saturns around F stars, several multiplanetary systems in a variety of architectures. These results show that a wealth of planetary systems still remains in the K2 data, some of which can be validated using minimal follow-up observations and taking advantage of analyses presented in previous catalogues.

中文翻译：

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37 个新的经过验证的行星在重叠的 K2 战役中

我们分析了 NASA K2 任务的第 5 次和第 6 次战役（C5 和 C6）期间首次确定的 68 个候选行星系统。我们开始使用一系列后续观察来验证这些系统，包括自适应光学、散斑成像和侦察光谱。C5 与 C16 和 C18 以及 C6 与 C17 之间的重叠产生了具有长基线的光曲线，这使我们能够非常精确地测量凌日星历，重新审视早期活动中确定的单个凌日候选者，并寻找更多周期更长的凌日行星在以前的作品中可以检测到。使用 vespa，我们计算了 37 个候选者围绕 29 颗独特的主恒星运行的误报概率低于 1%，因此在统计上验证了它们是行星。这些行星的典型大小为 2.2 R⊕，轨道周期介于 1 之间。99 和 52.71 d。我们重点介绍了有趣的系统，包括 K2 探测到的周期最长的次海王星、围绕 F 星的次土星、各种架构中的多个多行星系统。这些结果表明，大量的行星系统仍然存在于 K2 数据中，其中一些可以通过最少的后续观察和利用以前目录中提供的分析来验证。